From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.7 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95110C48BE6 for ; Wed, 16 Jun 2021 06:18:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B7AD613BF for ; Wed, 16 Jun 2021 06:18:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbhFPGUK (ORCPT ); Wed, 16 Jun 2021 02:20:10 -0400 Received: from mail-ej1-f47.google.com ([209.85.218.47]:43556 "EHLO mail-ej1-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbhFPGUJ (ORCPT ); Wed, 16 Jun 2021 02:20:09 -0400 Received: by mail-ej1-f47.google.com with SMTP id nb6so1819423ejc.10; Tue, 15 Jun 2021 23:18:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=9a9qyUphW3s0CGsYm8ttvYCQCKXWvSpf1HL+27z8QW8=; b=uj7uj6nI2sbtu50QXp9uEjTBQNWC3nYoZhWc7DmUGSt9zrqnwyVcXwSpGvUkYZAKoH 4GUvIagJDXnwC9OeN9fYVPl+dh9xWi1SSqPiSJ2eNYmUfswtFzaf/jJNWXEv0JM7Chn6 7XOPe61tV7WaN+2cGFl2nXDek41SmA8z1TkTHryv3H+//abwtmVTlWYA0T7V7F9usScp 4sqaFyq6r2jPqSy35DkcOMqtxRMngspN90yP/VjzFdoLHSes8KSFWtZEqafTDEQ65DaQ 1KpS6XD/sNpbHNjpemu1Iq87gVmRdbPKZ1eqmcxCIbcuLCbGDbMSBYXPa+2qRhjoysJ1 AdrA== X-Gm-Message-State: AOAM533SLfKgOtqDF5PWggS6aJc2R6KMlFfx+P86Rje8YWBJIFgDnpuv gKkbkcBIM6tVh4T7i9B18zZEvQkGZfE= X-Google-Smtp-Source: ABdhPJwzHVZX4Ev+IXHg2PqEMD3Z6TJAkvcxUGu8B+NUNesinhBoStuxVviQJgnTwZyugiHlJqe2vQ== X-Received: by 2002:a17:906:b24a:: with SMTP id ce10mr3511669ejb.83.1623824282553; Tue, 15 Jun 2021 23:18:02 -0700 (PDT) Received: from ?IPv6:2a0b:e7c0:0:107::70f? ([2a0b:e7c0:0:107::70f]) by smtp.gmail.com with ESMTPSA id v7sm916032edx.38.2021.06.15.23.18.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Jun 2021 23:18:01 -0700 (PDT) Subject: Re: [PATCH] serial: amba-pl011: add RS485 support To: Lino Sanfilippo , gregkh@linuxfoundation.org Cc: linux@armlinux.org.uk, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210610135004.7585-1-LinoSanfilippo@gmx.de> From: Jiri Slaby Message-ID: <5f00ff43-9287-4027-7d80-474da957703c@kernel.org> Date: Wed, 16 Jun 2021 08:18:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210610135004.7585-1-LinoSanfilippo@gmx.de> Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10. 06. 21, 15:50, Lino Sanfilippo wrote: > Add basic support for RS485: Provide a callback to configure rs485 > settings. Handle the RS485 specific part in the functions > pl011_rs485_tx_start() and pl011_rs485_tx_stop() which extend the generic > start/stop callbacks. > Beside via IOCTL from userspace RS485 can be enabled by means of the > device tree property "rs485-enabled-at-boot-time". > > Signed-off-by: Lino Sanfilippo > --- > This patch has been tested with a Raspberry Pi CM3. > > drivers/tty/serial/amba-pl011.c | 143 +++++++++++++++++++++++++++++++- > 1 file changed, 140 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index 78682c12156a..36e8b938cdba 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c ... > @@ -1380,6 +1415,31 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, > return true; > } > > +static void pl011_rs485_tx_start(struct uart_amba_port *uap) > +{ > + struct uart_port *port = &uap->port; > + u32 cr; > + > + /* Enable transmitter */ > + cr = pl011_read(uap, REG_CR); > + cr |= UART011_CR_TXE; > + /* Disable receiver if half-duplex */ > + if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) > + cr &= ~UART011_CR_RXE; > + > + if (port->rs485.flags & SER_RS485_RTS_ON_SEND) > + cr &= ~UART011_CR_RTS; > + else > + cr |= UART011_CR_RTS; > + > + pl011_write(cr, uap, REG_CR); > + > + if (port->rs485.delay_rts_before_send) > + mdelay(port->rs485.delay_rts_before_send); This is up to 1 second delay with interrupts disabled. Definitely not nice. 8250 clamps this to 100 ms at least, why did you choose 1000 ms? > + > + uap->rs485_tx_started = true; > +} > + > /* Returns true if tx interrupts have to be (kept) enabled */ > static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) > { ... > @@ -1941,6 +2021,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, > unsigned int lcr_h, old_cr; > unsigned long flags; > unsigned int baud, quot, clkdiv; > + unsigned int bits; > > if (uap->vendor->oversampling) > clkdiv = 8; > @@ -1968,25 +2049,32 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, > switch (termios->c_cflag & CSIZE) { > case CS5: > lcr_h = UART01x_LCRH_WLEN_5; > + bits = 7; > break; > case CS6: > lcr_h = UART01x_LCRH_WLEN_6; > + bits = 8; > break; > case CS7: > lcr_h = UART01x_LCRH_WLEN_7; > + bits = 9; > break; > default: // CS8 > lcr_h = UART01x_LCRH_WLEN_8; > + bits = 10; > break; > } > - if (termios->c_cflag & CSTOPB) > + if (termios->c_cflag & CSTOPB) { > lcr_h |= UART01x_LCRH_STP2; > + bits++; > + } > if (termios->c_cflag & PARENB) { > lcr_h |= UART01x_LCRH_PEN; > if (!(termios->c_cflag & PARODD)) > lcr_h |= UART01x_LCRH_EPS; > if (termios->c_cflag & CMSPAR) > lcr_h |= UART011_LCRH_SPS; > + bits++; > } You can do simply: bits = tty_get_frame_size(termios->c_cflag); now: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-testing&id=3ec2ff37230e1c961d4b0d0118dd23c46b5bcdbb thanks, -- js